WASHINGTON — The House today passed a scaled-down version of a massive farm bill, putting off a fight over food stamp spending and giving Republican leaders a victory after a decisive defeat on the larger bill last month. The GOP leaders scrambled to get the bill to the floor today and gather enough votes this week after making a decision to drop a politically sensitive food stamp section of the bill and pass legislation that contained only farm programs. The plan faced opposition from Democrats, farm groups and conservative groups. But Majority Leader Eric Cantor of Virginia navigated his colleagues to a 216-208 vote by convincing Republican members that this was the best chance to get the bill passed and erase the embarrassment of the June defeat.